Portion of a roller skate



FIG. 1 is a perspective view of a roller skate, seen from the front and right sides thereof, showing our new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a front end view thereof.

The broken line showing of other parts of the roller skate shown in the drawing is for illustrative purposes only and forms no part of the claimed design. 

We claim the ornamental design for a portion of a roller skate, as shown and described. 